Pertussis (Whooping Cough) | Osmosis Study Video

Summary

Pertussis, or whooping cough, is a highly contagious respiratory infection caused by *Bordetella pertussis*. It starts with mild symptoms and progresses to severe coughing fits followed by a whooping sound. The bacteria release toxins that damage the respiratory system, causing swelling, mucus buildup, and difficulty breathing. Early diagnosis and treatment with antibiotics are key to managing the disease. Vaccination, especially through the DTaP vaccine, is crucial for prevention. Pertussis can be deadly for infants, making vaccination and timely medical intervention vital for reducing risks.

Takeaways

• 😀 Pertussis, also known as whooping cough, is caused by the bacteria Bordetella pertussis, which leads to violent coughing fits that make it difficult to breathe.
• 😀 The bacteria can spread through droplets from coughing or sneezing and can also survive for several days on surfaces, making it possible to contract through contact with contaminated surfaces.
• 😀 Bordetella pertussis produces several toxins, including filamentous hemagglutinin, pertactin, and agglutination, which help the bacteria attach to the respiratory epithelial cells.
• 😀 The tracheal cytotoxin paralyzes the cilia in the respiratory tract, preventing the body from clearing mucus, which causes persistent coughing.
• 😀 Pertussis toxin increases the number of T-cells in the blood and makes blood vessels in the respiratory tissue more sensitive to histamine, contributing to airway swelling and difficulty breathing.
• 😀 Adenylate cyclase toxin prevents phagocytes from killing the bacteria and even induces their self-destruction through apoptosis.
• 😀 The disease progresses through three stages: the catarrhal phase (early symptoms), the paroxysmal phase (violent coughing fits), and the convalescent phase (recovery).
• 😀 The catarrhal phase is the most contagious, and symptoms include cough, congestion, and sometimes a low-grade fever.
• 😀 In the paroxysmal phase, intense coughing fits with a whooping sound occur, and in infants, it can lead to severe complications such as apnea and life-threatening events.
• 😀 Pertussis can be diagnosed through nasopharyngeal swabbing, DNA identification, or serology tests. Early diagnosis and antibiotic treatment are key to reducing damage and transmission.
• 😀 Vaccination with the DTaP vaccine provides over 90% effectiveness in preventing pertussis and is essential for controlling outbreaks, particularly among unvaccinated individuals and the elderly.

Q & A

What is pertussis, and what causes it?

Pertussis, also known as whooping cough, is a contagious respiratory infection caused by the bacterium *Bordetella pertussis*. It is characterized by violent coughing spells known as paroxysms, which make it difficult to breathe.

How is pertussis transmitted?

Pertussis is transmitted from one person to another through droplets expelled during sneezing or coughing. The bacteria can also survive on dry surfaces for several days, making it possible to contract pertussis by touching contaminated surfaces.

What are the key toxins released by Bordetella pertussis?

Bordetella pertussis releases several toxins: filamentous hemagglutinin, pertactin, agglutination toxins, tracheal cytotoxin, pertussis toxin, and adenylate cyclase toxin. These toxins help the bacteria attach to respiratory epithelial cells, paralyze cilia, and cause inflammation, mucus buildup, and immune system disruptions.

How does pertussis toxin affect the immune system?

Pertussis toxin stimulates T cells to divide and migrate into circulation, preventing them from leaving the blood to enter tissues. It also causes an increase in lymphocyte levels in the blood and makes blood vessels in the respiratory tract more sensitive to histamine, leading to swelling and difficulty breathing.

What happens during the incubation period of pertussis?

The incubation period is the time between the bacterium entering the body and the onset of symptoms, typically lasting about a week. During this phase, the bacteria begin to colonize the respiratory tract without causing noticeable damage.

What is the paroxysmal phase of pertussis?

The paroxysmal phase lasts one to six weeks and is marked by severe coughing fits (paroxysms) followed by a whooping sound as the patient struggles to breathe. This phase can lead to complications such as vomiting, broken ribs, and even collapsed lungs.

What complications can arise from pertussis, especially in infants?

In infants, pertussis can cause severe complications like apnea, cyanosis (lack of oxygen), seizures, and encephalopathy. The infection can even be fatal. Additionally, infants may experience life-threatening events called apneas, where breathing temporarily stops.

Why is it important to diagnose pertussis early?

Early diagnosis during the catarrhal phase allows for the use of antibiotics to kill the bacteria, reducing the overall damage caused by the infection. Early treatment is essential to limit the severity of the disease.

How is pertussis diagnosed?

Pertussis can be diagnosed by swabbing the nasopharynx to grow the bacteria in culture, using polymerase chain reaction (PCR) to identify bacterial DNA, or detecting *Bordetella pertussis* antigens using a direct fluorescent antibody test. Serology may also be used to detect antibodies produced in response to the infection.

How does vaccination help prevent pertussis?

Vaccination, particularly with the DTaP vaccine (diphtheria, tetanus, acellular pertussis), is over 90% effective in preventing pertussis. It helps to avoid infection or lessen the symptoms if it occurs. Vaccination is particularly important in young infants and individuals with weakened immune systems.